Title:Design and Manufacturing of a TUBE ROTATOR Date: January-2015
Team K03-2014: Lampousis Charalampos, Michas Serafeim, Papachristopoulou Marina, Students, Dept. of Mechanical Engineering, NTUA, Greece
Short Abstract Design and manufacturing of a device meeting the needs of general biological sample mixing.
Acknowledgements We would like to thank George Kanakaris, Nikos Kavalopoulos and Alex Polesiuk for assisting us with the development and manufacturing of our project.
Also we would like to thank our professor Mr. Alexopoulos for giving us the opportunity to study and manufacture a widely used device.
Introduction A TUBE ROTATOR is a device, mainly used in biological laboratories, that achieves automatic mixing of biological samples. The tubes that contain these samples are being revolved with low speed around an axis which is powered by an electrical motor.
The use of a device like this facilitates the work of biologists who want rapid and easy mixing, homogenization and dissolution of solid substances in aqueous and alcoholic solutions.
Examples of Tube Rotators
Usability Specifications The device had to meet the needs of the bioengineering laboratory of NTUA, where it was going to be used, which are:
Large capacity and multi-size diameter of tubes
Automatic, continuous and quiet function
Revolution speed control
Brand new and innovative design
Specification Implementation In order to accomplish the aforementioned goals the device had to contain the following parts:
Removable plates with various diameter holes where the tubes fit in
A DC motor with sufficient torque to revolve plates filled with tubes
A potentiometer to adjust the current passing through the motor
The Basic Concept
Two plates, each one mounted on two concentric axes, revolve powered by a DC motor. According to the lab’s needs we designed two types of plates, one that can host only tubes of 5ml and one that can host 5ml, 15ml, 50ml tubes with 33% percentage of each size. In every case, our design can hold 98 – 104 tubes each time.
The plates had to be synchronized revolving with a relative angle of 90o, so that any collision between tubes could be avoided.
Therefore, we had to design a power transmission system that revolves both of the plates with just one motor, keeping the relative angle at 90o. First Design
For the aesthetic part, we decided our frame to have a rabbit's head shape.
For the transmission part, our first idea was to use 3 pulleys with a belt. The small pulley would be powered by the motor, while the other two, which have the same diameter would be rotated using the belt and the small pulley’s motion.
This design’s disadvantages were:
In case of excessive weight on the plates, slip between the pulleys and the belt could happen. Such a thing would end up losing the angle correlation between the plates.
Manufacturing of the pulleys required a lot of difficult machining.
Final Design
In order to overcome the aforementioned disadvantages, the pulleys were replaced by gears, thus eliminating slip. In addition, because the gears are made of plexiglass, machining is easy using only a laser cutter.
This also contributed to the device's silent function.
In this final design our Tube Rotator has the following specifications:
User friendly design
Large capacity and multi-size diameter of tubes
Lightweight (2.8 kg) and tough construction that allows portability.
Rotation speed modulation
Silent function
Materials Used
Plexiglass for the frame, the plates and the gears
Aluminum for the axes, for stiffness and small weight
Ball bearings for minimum friction between the axes and the frame
A DC motor with gearbox with sufficient torque
220V to 12V AC Adapter
A potentiometer and an on/off switch
Byproducts The plates are removable and can be used as a base outside the device, so that the next batch of tubes can be prepared for mixing without losing time.
Future Work
Use of proper sealing so that the device can be used under 100% humidity conditions and high temperatures inside an incubator.
Use of automatic control for intermittent function, change of rotation and countdown timer implementation.
Date: January-2015
Team K03-2014:
Lampousis Charalampos,
Michas Serafeim,
Papachristopoulou Marina,
Students, Dept. of Mechanical Engineering, NTUA, Greece
Short Abstract
Design and manufacturing of a device meeting the needs of general biological sample mixing.
Acknowledgements
We would like to thank George Kanakaris, Nikos Kavalopoulos and Alex Polesiuk for assisting us with the development and manufacturing of our project.
Also we would like to thank our professor Mr. Alexopoulos for giving us the opportunity to study and manufacture a widely used device.
Introduction
A TUBE ROTATOR is a device, mainly used in biological laboratories, that achieves automatic mixing of biological samples. The tubes that contain these samples are being revolved with low speed around an axis which is powered by an electrical motor.
The use of a device like this facilitates the work of biologists who want rapid and easy mixing, homogenization and dissolution of solid substances in aqueous and alcoholic solutions.
Examples of Tube Rotators
Usability Specifications
The device had to meet the needs of the bioengineering laboratory of NTUA, where it was going to be used, which are:
Specification Implementation
In order to accomplish the aforementioned goals the device had to contain the following parts:
The Basic Concept
Two plates, each one mounted on two concentric axes, revolve powered by a DC motor. According to the lab’s needs we designed two types of plates, one that can host only tubes of 5ml and one that can host 5ml, 15ml, 50ml tubes with 33% percentage of each size. In every case, our design can hold 98 – 104 tubes each time.
The plates had to be synchronized revolving with a relative angle of 90o, so that any collision between tubes could be avoided.
Therefore, we had to design a power transmission system that revolves both of the plates with just one motor, keeping the relative angle at 90o.
First Design
For the aesthetic part, we decided our frame to have a rabbit's head shape.
For the transmission part, our first idea was to use 3 pulleys with a belt. The small pulley would be powered by the motor, while the other two, which have the same diameter would be rotated using the belt and the small pulley’s motion.
This design’s disadvantages were:
Final Design
In order to overcome the aforementioned disadvantages, the pulleys were replaced by gears, thus eliminating slip. In addition, because the gears are made of plexiglass, machining is easy using only a laser cutter.
This also contributed to the device's silent function.
In this final design our Tube Rotator has the following specifications:
Materials Used
Byproducts
The plates are removable and can be used as a base outside the device, so that the next batch of tubes can be prepared for mixing without losing time.
Future Work
Photos/Videos of the final product
References